ATI Radeon HD 4800 Graphics Architecture: Long Anticipated Revenge?

We have been waiting for new graphics architecture from ATI for a long time, especially since the previous ATI Radeon HD generation couldn’t compete successfully against high-performance Nvidia solutions. Will ATI Radeon HD 4800 prove up to everyone’s expectations? Let’s try answering this question from the theoretical prospective and also check out the first graphics accelerator based on the new ATI RV770 chip – Power Color Radeon HD 4850 512MB.

AMD’s graphics department ATI has not been doing quite fine lately. The company has not been able to introduce a graphics architecture that would be truly competitive against Nvidia’s GeForce 8/9, especially in the top-performance sector. Even though not a complete failure, the ATI Radeon HD 2900 was far from a success. This hot and uneconomical GPU was noticeably inferior to Nvidia’s G80-based solutions mostly due to questionable architectural solutions such as the superscalar architecture of the execution units and the lame design of the texture modules coupled with the insufficient amount thereof.

ATI’s profits had declined dramatically but the release of the next GPU, codenamed RV670 and installed on the ATI Radeon HD 3800 series, helped improve the situation somewhat. The new GPU was free from the drawbacks of the R600 chip but lacked any really new features of its own. The only breakthrough was the 55mm manufacturing process. Otherwise, the RV670 inherited the R600 architecture, acquired support for UVD and DirectX 10.1, but lost the 512-bit external memory bus. The ATI Radeon HD 3870 and 3850 became bestsellers among gamers who could not afford to spend over $250 for their graphics card as these solutions delivered acceptable performance at a reasonable price. And it is no secret that mainstream products account for the largest share in total sales.

Later on, the ATI Radeon HD 3000 series was complemented with the unique dual-processor Radeon HD 3870 X2. ATI proved its ability to be a technological leader, even though for a little while. The release of the Nvidia GeForce 9800 GX2 made it obvious that the potential of ATI’s Radeon HD 2000/3000 architectures had been exhausted. It also became more and more obvious that the era of monolithic monster chips was approaching its end. Trying to reach higher performance the developers were increasing the size, complexity and power consumption of the GPUs but the chip yield was lowering while the manufacturing cost was growing up. As a result, a graphics card with such a monster chip just could not be inexpensive.

Drawing on its experience of developing the ATI Radeon HD 3870 X2, AMD decided to default from the next round of the race for packing more and more execution subunits into the single graphics processor. It was not AMD’s goal to develop the largest, powerful, and most expensive GPU in the world although AMD might have tried to do that. The company has enough development resources whatever Nvidia can say. Instead, the RV770 is the result of a new strategic concept. The key of the concept is a relatively inexpensive but fast GPU that should meet the requirements of the bulk of gamers. Graphics cards with the new chip are expected to cost about $300 whereas enthusiasts who want to have maximum performance irrespective of the price can be satisfied by means of multi-chip solutions such as ATI Radeon HD 3870 X2.

As we noted in our ATI Radeon HD 3870 X2 review, this approach has its downsides, yet it has a lot of advantages, too. First of all, it targets the main category of users. Second, solutions with higher performance can be created easily. Designing a dual-chip graphics card takes more effort and time than developing a higher-performance monolithic graphics core from scratch. Clearly, ATI’s new chip must be as fast as the best single-chip solutions of the previous generation for this strategy to work.

This review is going to give you the answer about the potential of the new graphics solutions from ATI Technologies. We’ll discuss the details of the RV770 architecture and we’ll start with telling you the characteristics of RV770-based graphics cards.